This video shows a group known as Critical Mass, an international cyclist advocacy group, driving into oncoming traffic on the wrong side of the road in San Francisco.

One cyclist slowing inches his way toward a Zipcar and practically throws himself on the bumper.

"You f*cking hit my bike!" he shouts, as other cyclists surround the car and yell at the driver. The driver, obviously threatened, pulls away and tries to escape before a cyclist hits the car multiple times with a U-lock.

The group's website encourages cyclists to "remember that pleasure and friendliness are more subversive than anger and blaming."

A woman was tailgating a car in Northern California this weekend, and she went full speed towards Crazy Town after the passengers made "a rude hand gesture" to her.

The 50-year-old woman, Dierdre Orozco, drove her Ford Explorer in front of the girls to get them to stop. She also pretended to be a police officer, even getting out of her car at one point and approaching them with some sort of ID.

When this strategy failed, she decided to start ramming them off the road.